Measurement of parameters in reactors having moving stirrers

Abstract

A process and apparatus for the measurement of parameters in reactors having moving stirrers which contain probes in the reactor interior, wherein at least two probes connected via a multiplexer to a sensor signal amplifier by connecting cables located in the moving stirrers are installed on the surface of the moving stirrers, and the measurement data obtained by the probes are passed via the connecting cables to a sensor signal amplifier and from thence are passed on to an electronic evaluation unit by non-contact, inductive signal transmission by means of a contactless sensor tap.

We claim: 
     
       1. A process for the measurement of parameters in reactors having moving stirrers which contain probes in the reactor interior, wherein at least two probes connected to a sensor signal amplifier by connecting cables located in the moving stirrers are installed on the surface of the moving stirrers, and the measurement data obtained by the probes are passed via the connecting cables to a sensor signal amplifier and from thence are passed on to an electronic evaluation unit by non-contact, inductive signal transmission by means of a contactless sensor tap. 
     
     
       2. A process as claimed in claim 1, wherein the probes used are pressure probes. 
     
     
       3. A process as claimed in claim 1, wherein the probes used are temperature probes. 
     
     
       4. A process as claimed in claim 1, wherein the probes arranged on the surface of the moving stirrer are thermally insulated from the highly thermoconductive moving stirrer by being embedded in plastic bushes, the plastic used having less than 1% of the thermoconductivity of the steel forming the stirrer helix. 
     
     
       5. A process as claimed in claim 1, wherein the moving stirrer used is a self-supporting helical stirrer. 
     
     
       6. A process as claimed in claim 5, wherein the measurement data entering the sensor signal amplifier are transmitted via a coaxial cable to an encapsulated rotor antenna, from where they are then transmitted, by non-contact, inductive signal transmission, to an encapsulated stator antenna located in a central dip tube in the center of the self-supporting helical stirrer, the measurement data subsequently being passed on from the encapsulated stator antenna to the electronic evaluation unit via a further coaxial cable. 
     
     
       7. A process as claimed in claim 5, wherein the voltage supply required for the parameter measurement is simultaneously effected via the encapsulated rotor and stator antennae, likewise inductively. 
     
     
       8. A process as claimed in claim 1, wherein the reactor is operated at a pressure in the range from 0 to 100 bar and at a temperature in the range from -40 to +150° C. 
     
     
       9. A process as claimed in claim 8, wherein the reactor is a polymerization reactor operated at a pressure in the range from 10 to 50 bar at a temperature in the range from 40 to +150° C. 
     
     
       10. A device for determining parameters in reactors having moving stirrers which contain probes in the reactor interior, at least two probes connected to a sensor signal amplifier by connecting cables located in the moving stirrer being installed on the surface of the moving stirrer, the amplifier being in turn connected to an electronic evaluation unit via a contactless sensor tap. 
     
     
       11. A device as claimed in claim 10, in which temperature probes are installed on the surface of the moving stirrer. 
     
     
       12. A device as claimed in claim 10, in which pressure probes are installed on the surface of the moving stirrer.